Gene Symbol: TOC1
Description: CCT motif -containing response regulator protein
Alias: APRR1, AtTOC1, MFB13.13, MFB13_13, PRR1, PSEUDO-RESPONSE REGULATOR 1, TIMING OF CAB EXPRESSION 1, CCT motif -containing response regulator protein
Species: thale cress
Products:     TOC1

Top Publications

  1. Ito S, Nakamichi N, Nakamura Y, Niwa Y, Kato T, Murakami M, et al. Genetic linkages between circadian clock-associated components and phytochrome-dependent red light signal transduction in Arabidopsis thaliana. Plant Cell Physiol. 2007;48:971-83 pubmed
    ..The originally described member of PRRs is TOC1 (or PRR1) (TIMING OF CAB EXPRESSION 1). Interestingly, seedlings of A. thaliana carrying a certain lesion (i.e...
  2. Pokhilko A, Fernández A, Edwards K, Southern M, Halliday K, Millar A. The clock gene circuit in Arabidopsis includes a repressilator with additional feedback loops. Mol Syst Biol. 2012;8:574 pubmed publisher
    ..Pseudo-Response Regulator 9 was repressed by an evening gene, previously identified with Timing Of CAB Expression1 (TOC1)...
  3. Mas P, Kim W, Somers D, Kay S. Targeted degradation of TOC1 by ZTL modulates circadian function in Arabidopsis thaliana. Nature. 2003;426:567-70 pubmed
    ..we provide genetic and molecular evidence for a role of ZEITLUPE (ZTL) in the targeted degradation of TIMING OF CAB EXPRESSION 1 (TOC1) in Arabidopsis thaliana (thale cress)...
  4. Kim W, Fujiwara S, Suh S, Kim J, Kim Y, Han L, et al. ZEITLUPE is a circadian photoreceptor stabilized by GIGANTEA in blue light. Nature. 2007;449:356-60 pubmed
    ..normal circadian period by controlling the proteasome-dependent degradation of a central clock protein, TIMING OF CAB EXPRESSION 1 (TOC1)...
  5. Martin Tryon E, Kreps J, Harmer S. GIGANTEA acts in blue light signaling and has biochemically separable roles in circadian clock and flowering time regulation. Plant Physiol. 2007;143:473-86 pubmed
    ..Gene expression and epistasis analyses show that TIMING OF CHLOROPHYLL A/B BINDING PROTEIN1 (TOC1) expression is not solely dependent upon GI and that GI expression is only indirectly affected by TOC1, suggesting ..
  6. Legnaioli T, Cuevas J, Mas P. TOC1 functions as a molecular switch connecting the circadian clock with plant responses to drought. EMBO J. 2009;28:3745-57 pubmed publisher
    ..A key clock component (TOC1, timing of CAB expression 1) binds to the promoter of the ABA-related gene (ABAR/CHLH/GUN5) and controls its circadian expression...
  7. Harmon F, Imaizumi T, Gray W. CUL1 regulates TOC1 protein stability in the Arabidopsis circadian clock. Plant J. 2008;55:568-79 pubmed publisher
    ..In Arabidopsis thaliana, establishment of the circadian period relies on targeted degradation of TIMING OF CAB EXPRESSION 1 (TOC1) by the 26S proteasome...
  8. Farinas B, Mas P. Functional implication of the MYB transcription factor RVE8/LCL5 in the circadian control of histone acetylation. Plant J. 2011;66:318-29 pubmed publisher
    ..Similar to CCA1, RVE8/LCL5 regulates the expression of the oscillator gene TOC1 (TIMING OF CAB EXPRESSION1) by associating with the TOC1 promoter and by modulating the pattern of histone 3 (H3) ..
  9. Ito S, Matsushika A, Yamada H, Sato S, Kato T, Tabata S, et al. Characterization of the APRR9 pseudo-response regulator belonging to the APRR1/TOC1 quintet in Arabidopsis thaliana. Plant Cell Physiol. 2003;44:1237-45 pubmed
    ..TOC1 is a member of a small family of proteins, designated as ARABIDOPSIS PSEUDO-RESPONSE REGULATORS (APRR1/TOC1, APRR3, APRR5, APRR7, and APRR9)...

More Information


  1. Makino S, Matsushika A, Kojima M, Yamashino T, Mizuno T. The APRR1/TOC1 quintet implicated in circadian rhythms of Arabidopsis thaliana: I. Characterization with APRR1-overexpressing plants. Plant Cell Physiol. 2002;43:58-69 pubmed
    ..the Myb-related CCA1 and LHY transcription factors and a member of the novel family of pseudo response regulators (APRR1/TOC1)...
  2. Strayer C, Oyama T, Schultz T, Raman R, Somers D, Mas P, et al. Cloning of the Arabidopsis clock gene TOC1, an autoregulatory response regulator homolog. Science. 2000;289:768-71 pubmed
    The toc1 mutation causes shortened circadian rhythms in light-grown Arabidopsis plants. Here, we report the same toc1 effect in the absence of light input to the clock...
  3. Ding Z, Doyle M, Amasino R, Davis S. A complex genetic interaction between Arabidopsis thaliana TOC1 and CCA1/LHY in driving the circadian clock and in output regulation. Genetics. 2007;176:1501-10 pubmed
    ..been proposed that CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY) together with TIMING OF CAB EXPRESSION 1 (TOC1) make up the central oscillator of the Arabidopsis thaliana circadian clock...
  4. Kevei E, Gyula P, Hall A, Kozma Bognar L, Kim W, Eriksson M, et al. Forward genetic analysis of the circadian clock separates the multiple functions of ZEITLUPE. Plant Physiol. 2006;140:933-45 pubmed
    ..interactions with previously described partner proteins Arabidopsis S-phase kinase-related protein 1, TIMING OF CAB EXPRESSION 1, and PHYB. Interaction with PHYB was unaffected by mutation of any ZTL domain...
  5. Kikis E, Khanna R, Quail P. ELF4 is a phytochrome-regulated component of a negative-feedback loop involving the central oscillator components CCA1 and LHY. Plant J. 2005;44:300-13 pubmed
    ..loop formed by the genes CIRCADIAN CLOCK ASSOCIATED (CCA1), LATE ELONGATED HYPOCOTYL (LHY) and TIMING OF CAB (TOC1) constitutes the core of the central oscillator of the circadian clock in Arabidopsis...
  6. Baudry A, Ito S, Song Y, Strait A, Kiba T, Lu S, et al. F-box proteins FKF1 and LKP2 act in concert with ZEITLUPE to control Arabidopsis clock progression. Plant Cell. 2010;22:606-22 pubmed publisher
    ..In addition, FKF1 and LKP2 also interacted with TIMING OF CAB EXPRESSION1 (TOC1) and PSEUDO-RESPONSE REGULATOR5 (PRR5), and both proteins were further stabilized in ztl fkf1 and ztl fkf1 lkp2 ..
  7. Huang W, Pérez García P, Pokhilko A, Millar A, Antoshechkin I, Riechmann J, et al. Mapping the core of the Arabidopsis circadian clock defines the network structure of the oscillator. Science. 2012;336:75-9 pubmed publisher
    ..In Arabidopsis, oscillator coupling relies on a core loop in which the evening oscillator component TIMING OF CAB EXPRESSION 1 (TOC1) was proposed to activate a subset of morning-expressed oscillator genes...
  8. Wang L, Fujiwara S, Somers D. PRR5 regulates phosphorylation, nuclear import and subnuclear localization of TOC1 in the Arabidopsis circadian clock. EMBO J. 2010;29:1903-15 pubmed publisher
    ..b>TOC1/PRR1, a pseudoresponse regulator (PRR) protein, is a central element in one of the feedback loops of the ..
  9. Gendron J, Pruneda Paz J, Doherty C, Gross A, Kang S, Kay S. Arabidopsis circadian clock protein, TOC1, is a DNA-binding transcription factor. Proc Natl Acad Sci U S A. 2012;109:3167-72 pubmed publisher
    ..described feedback loop of the Arabidopsis circadian clock is based on reciprocal regulation between Timing of CAB Expression 1 (TOC1) and Circadian Clock-associated 1 (CCA1)/late elongated hypocotyl (LHY)...
  10. Para A, Farré E, Imaizumi T, Pruneda Paz J, Harmon F, Kay S. PRR3 Is a vascular regulator of TOC1 stability in the Arabidopsis circadian clock. Plant Cell. 2007;19:3462-73 pubmed
    ..The founding member of the family, TIMING OF CAB EXPRESSION1 (TOC1), is an essential component of the transcriptional network that constitutes the core mechanism of the circadian ..
  11. Fujiwara S, Wang L, Han L, Suh S, Salome P, McClung C, et al. Post-translational regulation of the Arabidopsis circadian clock through selective proteolysis and phosphorylation of pseudo-response regulator proteins. J Biol Chem. 2008;283:23073-83 pubmed publisher
    ..Peak expression of TOC1 (timing of cab expression 1)/PRR1, PRR3, PRR5, PRR7, and PRR9 are each phased differently over the course of the day and loss of any ..
  12. Hemmes H, Henriques R, Jang I, Kim S, Chua N. Circadian clock regulates dynamic chromatin modifications associated with Arabidopsis CCA1/LHY and TOC1 transcriptional rhythms. Plant Cell Physiol. 2012;53:2016-29 pubmed publisher
    ..CIRCADIAN CLOCK ASSOCIATED 1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) and TIMING OF CAB EXPRESSION 1 (TOC1) reciprocally repress genes encoding each other and are critical for the generation of circadian ..
  13. Thain S, Vandenbussche F, Laarhoven L, Dowson Day M, Wang Z, Tobin E, et al. Circadian rhythms of ethylene emission in Arabidopsis. Plant Physiol. 2004;136:3751-61 pubmed
    ..In addition, ethylene production is controlled by the TIMING OF CAB EXPRESSION 1 and CIRCADIAN CLOCK ASSOCIATED 1 genes, which are critical for all circadian rhythms yet tested in ..
  14. Jones M, HARMER S. JMJD5 Functions in concert with TOC1 in the arabidopsis circadian system. Plant Signal Behav. 2011;6:445-8 pubmed
    ..recently identified a novel component of the Arabidopsis circadian clock, JMJD5, based on its coexpression with TOC1, an evening-phased component of the molecular oscillator...
  15. Niinuma K, Someya N, Kimura M, Yamaguchi I, Hamamoto H. Circadian rhythm of circumnutation in inflorescence stems of Arabidopsis. Plant Cell Physiol. 2005;46:1423-7 pubmed
    ..b>toc1 appears to shorten the period and elf3 causes an arrhythmic phenotype in circumnutation speed in LL, suggesting ..
  16. Matsushika A, Makino S, Kojima M, Yamashino T, Mizuno T. The APRR1/TOC1 quintet implicated in circadian rhythms of Arabidopsis thaliana: II. Characterization with CCA1-overexpressing plants. Plant Cell Physiol. 2002;43:118-22 pubmed
    ..a novel class of proteins, named pseudo-response regulators (APRRs) in Arabidopsis thaliana, each of which (APRR1, APRR3, APRR5, APRR7, and APRR9) has an intriguing structural design containing an N-terminal pseudo receiver ..
  17. Ito S, Kawamura H, Niwa Y, Nakamichi N, Yamashino T, Mizuno T. A genetic study of the Arabidopsis circadian clock with reference to the TIMING OF CAB EXPRESSION 1 (TOC1) gene. Plant Cell Physiol. 2009;50:290-303 pubmed publisher
    ..This tentative model consists of three interactive feedback loops, namely the core CCA1/LHY-TOC1/X loop, the morning CCA1/LHY-PRR9/PRR7 loop and the evening Y-TOC1 loop, in which the undefined Y gene might be GI...
  18. Yasuhara M, Mitsui S, Hirano H, Takanabe R, Tokioka Y, Ihara N, et al. Identification of ASK and clock-associated proteins as molecular partners of LKP2 (LOV kelch protein 2) in Arabidopsis. J Exp Bot. 2004;55:2015-27 pubmed
    ..The two-hybrid analysis also demonstrated that LKP2 interacted with TOC1, a clock component, but not with CCA1 or LHY, negative regulators of TOC1 gene expression...
  19. Ding Z, Millar A, Davis A, Davis S. TIME FOR COFFEE encodes a nuclear regulator in the Arabidopsis thaliana circadian clock. Plant Cell. 2007;19:1522-36 pubmed
    ..Neither its abundance nor its cellular distribution was found to be clock regulated. We suggest that TIC encodes a nucleus-acting clock regulator working close to the central oscillator. ..
  20. Kurup S, Jones H, Holdsworth M. Interactions of the developmental regulator ABI3 with proteins identified from developing Arabidopsis seeds. Plant J. 2000;21:143-55 pubmed
    ..All the AIPs show homology to existing transcription factors and therefore they may function with ABI3 within the network of transcriptional regulators that control embryo development in Arabidopsis. ..
  21. Pruneda Paz J, Breton G, Para A, Kay S. A functional genomics approach reveals CHE as a component of the Arabidopsis circadian clock. Science. 2009;323:1481-5 pubmed publisher
    ..In Arabidopsis, a core loop is established between CCA1 and TOC1. Although CCA1 directly represses TOC1, the TOC1 protein has no DNA binding domains, which suggests that it cannot ..
  22. Li X, Ma D, Lu S, Hu X, Huang R, Liang T, et al. Blue Light- and Low Temperature-Regulated COR27 and COR28 Play Roles in the Arabidopsis Circadian Clock. Plant Cell. 2016;28:2755-2769 pubmed
    ..Finally, we report that COR27 and COR28 bind to the chromatin of TOC1 and PRR5 to repress their transcription, suggesting that their effects on rhythms are in part due to their ..
  23. Niwa Y, Ito S, Nakamichi N, Mizoguchi T, Niinuma K, Yamashino T, et al. Genetic linkages of the circadian clock-associated genes, TOC1, CCA1 and LHY, in the photoperiodic control of flowering time in Arabidopsis thaliana. Plant Cell Physiol. 2007;48:925-37 pubmed
    ..Nevertheless, the genetic linkages between the major clock-associated TOC1, CCA1 and LHY genes and the canonical CO-FT flowering pathway are less clear...
  24. Fujimori T, Yamashino T, Kato T, Mizuno T. Circadian-controlled basic/helix-loop-helix factor, PIL6, implicated in light-signal transduction in Arabidopsis thaliana. Plant Cell Physiol. 2004;45:1078-86 pubmed
    ..circadian-controlled transcription factor was previously suggested to interact with the clock component, TIMING OF CAB EXPRESSION 1 (TOC1)...
  25. Johansson M, McWatters H, Bako L, Takata N, Gyula P, Hall A, et al. Partners in time: EARLY BIRD associates with ZEITLUPE and regulates the speed of the Arabidopsis clock. Plant Physiol. 2011;155:2108-22 pubmed publisher
    ..This work highlights the importance of cross talk between the ubiquitination pathway and transcriptional control for regulation of the plant clock. ..
  26. Song H, Noh Y. Rhythmic oscillation of histone acetylation and methylation at the Arabidopsis central clock loci. Mol Cells. 2012;34:279-87 pubmed
    ..Translated LHY and CCA1 proteins repress the expression of TIMING OF CAB EXPRESSION 1 (TOC1), which peaks in the evening...
  27. Delis C, Krokida A, Tomatsidou A, Tsikou D, Beta R, Tsioumpekou M, et al. AtHESPERIN: a novel regulator of circadian rhythms with poly(A)-degrading activity in plants. RNA Biol. 2016;13:68-82 pubmed publisher
    ..overexpression of AtHESP in plant lines affects the expression and rhythmicity of the clock core oscillator genes TOC1 and CCA1...
  28. Soy J, Leivar P, González Schain N, Martín G, Diaz C, Sentandreu M, et al. Molecular convergence of clock and photosensory pathways through PIF3-TOC1 interaction and co-occupancy of target promoters. Proc Natl Acad Sci U S A. 2016;113:4870-5 pubmed publisher
    ..Here we show that the PIFs and the core clock component Timing of CAB expression 1 (TOC1) display coincident cobinding to the promoters of predawn-phased, growth-related genes under SD ..
  29. Arana M, Tognacca R, Estravis Barcalá M, Sánchez R, Botto J. Physiological and molecular mechanisms underlying the integration of light and temperature cues in Arabidopsis thaliana seeds. Plant Cell Environ. 2017;40:3113-3121 pubmed publisher
    ..mediated by phytochrome B requires the presence of functional PSEUDO-RESPONSE REGULATOR 7 (PRR7) and TIMING OF CAB EXPRESSION 1 (TOC1) alleles...
  30. Matsushika A, Makino S, Kojima M, Mizuno T. Circadian waves of expression of the APRR1/TOC1 family of pseudo-response regulators in Arabidopsis thaliana: insight into the plant circadian clock. Plant Cell Physiol. 2000;41:1002-12 pubmed
    The Arabidopsis pseudo-response regulator, APRR1, has a unique structural design containing a pseudo-receiver domain and a C-terminal CONSTANS motif...
  31. Hsu P, Devisetty U, Harmer S. Accurate timekeeping is controlled by a cycling activator in Arabidopsis. elife. 2013;2:e00473 pubmed publisher
    ..Further, our work suggests that the plant clock consists of a highly interconnected, complex regulatory network rather than of coupled morning and evening feedback loops. DOI: ..
  32. Yamashino T, Matsushika A, Fujimori T, Sato S, Kato T, Tabata S, et al. A Link between circadian-controlled bHLH factors and the APRR1/TOC1 quintet in Arabidopsis thaliana. Plant Cell Physiol. 2003;44:619-29 pubmed
    APRR1 (ARABIDPSIS PSUEDO-RESPONSE REGULATOR 1) (or TOC1, TIMING OF CAB EXPRESSION 1) is believed to be a crucial component of biological clocks of Arabidopsis thaliana. Nevertheless, its molecular function remains to be fully elucidated...
  33. Ito S, Niwa Y, Nakamichi N, Kawamura H, Yamashino T, Mizuno T. Insight into missing genetic links between two evening-expressed pseudo-response regulator genes TOC1 and PRR5 in the circadian clock-controlled circuitry in Arabidopsis thaliana. Plant Cell Physiol. 2008;49:201-13 pubmed publisher
    ..Among them, the evening-expressed TOC1 (TIMING OF CAB EXPRESSION 1) gene plays a role by forming a transcriptional feedback core loop together with the morning-expressed ..
  34. Xie Q, Wang P, Liu X, Yuan L, Wang L, Zhang C, et al. LNK1 and LNK2 are transcriptional coactivators in the Arabidopsis circadian oscillator. Plant Cell. 2014;26:2843-57 pubmed publisher
    ..activators of central clock components, including PSEUDO-RESPONSE REGULATOR5 (PRR5) and TIMING OF CAB EXPRESSION1 (TOC1)...
  35. Farinas B, Mas P. Histone acetylation and the circadian clock: a role for the MYB transcription factor RVE8/LCL5. Plant Signal Behav. 2011;6:541-3 pubmed
    ..factor CIRCADIAN CLOCK-ASSOCIATED1 (CCA1), RVE8/LCL5 binds to the promoter of key clock component TOC1 (Timing of CAB expression 1) and regulates its circadian expression...